Environmental test chamber

ABSTRACT

One aspect of the present invention is a system of fabricating a barrier wall between the testing and tester volumes of an environmental test chamber. This aspect may use a plurality of pallets adapted to receive a device under test and a testing apparatus, a framework adapted to receive a plurality of pallets, and a plurality of insulation bricks associated with the plurality of pallets. The insulation bricks may be adapted such that they can cooperate to form an insulating barrier between the device under test and the testing apparatus.

RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 09/631,055, filed on Aug. 1, 2000, and which claims priority fromProvisional Application No. 60/146,812, filed Aug. 2, 1999; ProvisionalApplication No. 60/146,988, filed Aug. 3, 1999; Provisional ApplicationNo. 60/158,280, filed Oct. 7, 1999; and Provisional Application No.60/170,939, filed Dec. 15, 1999.

TECHNICAL FIELD

This invention generally relates to environmental test chambers andapparatuses for use therein. More particularly, the present inventionrelates to a hard drive carrier, suitable for use in an environmentaltest chamber, having improved flexibility, mechanical stability,enhanced maintainability, and thermal uniformity. The present inventionalso relates to a barrier wall, and a method of construction thereof,for isolating a test area from a pseudo-ambient area in an environmentaltest chamber. In addition, the present invention relates to anenvironmental test chamber suitable for individual or small batchtesting.

BACKGROUND

Computer hard drives are usually subjected to a “burn in” testingprocedure conducted in an environmentally controlled test chamber. Thesechambers are designed to isolate the drive from vibrations whileapplying controlled temperature and humidity changes so that the drivemanufacturer can obtain accurate test results.

Computer hard drives are also usually subjected to thermal testing orenvironmental conditioning testing during the design and prototypingphases of the manufacturing process. This testing, also known as “finalverification” testing, is also typically conducted in largeenvironmental test chambers. The manufacturer selects the humidity, testtemperature, and airflow inside the test chamber so that it simulatesthe thermal stress range of conditions that the device under test isrealistically expected to “see” in its useful life. Alternatively, thehumidity, test temperature, and airflow may be selected to be somemultiple of the worst expected conditions. These tests can provide avaluable tool to verify product quality and reliability.

To optimize test time during burn-in and during final verificationtesting, the disk drive should be heated or cooled at a defined rateuntil the specific desired test temperature is reached while applyingspecified humidity. Accordingly, it is important to maintain a specificairflow over the drive during this phase to ensure that temperaturegradients within the drive are typical of the end use environment. Theairflow through the test chamber must also be sufficient to ensure aconsistent humidity and temperature variance throughout the chamberwhile dissipating the heat generated during the tests by the operatingdevice (typically about thirty watts per a disk drive), but not at alevel at which excessive localized cooling would fail to simulate thefinal operational environment of the devices under test.

Conventional environmental test chambers consist of one or two chambers.One chamber provides a controlled environmental space for the itemsunder test (the “testing chamber”), and is designed to provide heat andcool large numbers of disk drives, typically about 120 drives at a time.There is generally no feedback control from the drives, the control ofthe overall chamber temperature being the preferred mode of operation.Accordingly, significant temperature variations can and do occur withinthe testing chamber, which result in different temperatures for drivesat different locations. Another problem with conventional environmentaltest chambers is that all of the files in the chamber are heated/cooledtogether. Thus, these systems are inherently designed for batchprocessing.

The second “tester” chamber, if included, typically provides a space forthe tester hardware (in single chamber devices, the tester hardware issimply left out in the ambient air). The divider between the testing andtester chambers has customarily been a solid metal wall, with insulatedelectrical or other “as-needed” connections made via permanent holes inthe wall. This solid metal wall severely limits the flexibility ofapplications and makes any alteration to accommodate differentapplications a time consuming and expensive process. The solid metalwall also allows significant heat transfer between the two chambers.

The drives are typically held in a fixture or a carrier while theyundergo the burn-in or final verification testing procedures. Oneproblem with conventional fixtures or carriers is that they are prone totransferring mechanical vibrations to the drive under test. Conventionalholders or fixtures also fail to provide good air circulation around thedrive, contributing to thermal gradients of as much as thirty degreesCelsius. Both of these conditions are undesirable because they add noiseto the test results and generally reduce the utility of theenvironmental test chamber.

Another problem with current carrier designs is that they lack “userfriendliness.” These designs typically use a “swing type” or “barn door”latch that requires a large rotational motion to engage or disengage thepoint clamping site with the drive. These latching mechanisms also donot provide clear access to both ends of the drive when the latch isopen. These problems can interfere with cable connection andarrangement.

Yet another problem with current carrier designs is that they arerelatively expensive because they require a large amount of rawmaterials and a large number of parts. This problem is compoundedbecause conventional carrier designs are custom designed for a singleuse. For example, carriers built to test 3.5″ disk drives could not beused with 2.5″ drives. These problems increase the manufacturing andassembly cost of the carrier. Lack of flexibility is also a problem infor users who need to test a variety of devices, such as small batchmanufacturers and research facilities.

Ideally, an environmental testing chamber and carrier testing stationshould individually subject each device under test to its requiredenvironment, should allow for accurate and precise control of theenvironment, and should allow the devices under test to beloaded/unloaded individually for a continuous flow of products throughthe testing station. This ideal, however, must be weighed against itscost of implementation.

Clearly, there is a need for more flexible environmental test chamberand hard drive carrier capable of accommodating different applications.There is also a need for a simple and inexpensive hard drive carrierthat reduces vibration and improves airflow around the drive. Inaddition, there is a need for a more user friendly hard drive carrierthat simplifies clamping/unclamping and that provides clear access tothe ends of the drive at all times.

SUMMARY

The present invention provides an environmental test chamber and acarrier capable of accommodating different devices under test. Oneaspect of the present invention includes the concept of designing“pallets” to carry components from both the tester and tested device.These pallets may include “bricks” that each form a portion of thebarrier wall between the test environment and tester space. This brickand pallet system provides for easy construction of a thermal barrierand permits great flexibility and versatility in overall design.

Another aspect of the present invention is a system of fabricating abarrier wall between the testing and tester volumes of an environmentaltest chamber. One embodiment of this system comprises a plurality ofpallets adapted to receive a device under test and a testing apparatus,a framework adapted to receive the plurality of pallets in a mannerpermitting a balance between a maximized number of pallets and obtainingsuitable airflow and temperature uniformity in the test volume, and aplurality of insulation bricks associated with the plurality of pallets.The insulation bricks cooperate to form an insulating barrier betweenthe device under test and the testing apparatus. The insulation bricksalso cooperate to form a plenum capable of being purged by anappropriate heated purge gas flow.

Yet another aspect of the present invention is an environmental testchamber suitable for individual or small batch testing. One embodimentcomprises a test volume having an inlet; an air delivery system adaptedto deliver a flow of air to the inlet; and a drawer, received in thetest volume and in pneumatic communication with the inlet. Another testchamber embodiment comprises an air delivery system adapted to deliverair to a test volume and a plurality of drawers received in the testvolume and in pneumatic communication with the air delivery system.

Still another aspect of the present invention is a method of testing aplurality of electrical components. This method may comprise the acts ofoperably connecting a first electrical component to a first test drawer;inserting the first test drawer in a test unit; operably connecting asecond electrical component to a second test drawer; and inserting thesecond test drawer in the test unit. The test unit in this embodimentmay either subject the first electrical component and the secondelectrical component to similar environmental conditions or maysimultaneously subject them to different environmental conditions.

The present invention also provides a simple and inexpensive hard drivecarrier that reduces vibrations, improves airflow around the drive,simplifies clamping/unclamping, and provides clear access to the ends ofthe drive at all times. One embodiment comprises a frame defining a testbed, a clamp pad moveably connected to the frame, a cam operablyconnected to the clamp pad and adapted to actuate the clamp pad intooperable engagement with a hard drive. Some embodiments may alsocomprise an electrical assembly attached to the frame, the electricalassembly being adapted to communicate signals to and from the harddrive. The carrier may also have a first side member and a second sidemember that allow the same carrier to receive and releasibly hold both2.5 inch drives and 3.5 inch hard drives. The hard drive carrier of thepresent invention is particularly suitable for use with theenvironmental test chamber.

Another aspect of the invention is a carrier apparatus adapted fortesting different sized devices under test. One embodiment comprises afirst test bed adapted for operable connection with a first device undertest; and a second test bed adapted for operable connection with asecond device under test; wherein the first device under test is largerthan the second device under test. Another embodiment comprises a frame;and a clamp operably attached to the frame and adapted to selectivelyhold a first device under test and a second device under test; whereinthe first device under test is larger than the second device under test.In these embodiments, the first device under test may be a 3.5 inch harddrive and the second device under test may be a 2.5 inch hard drive.

One feature and advantage of the present invention is that it provides adual chamber environmental test chamber system that is easily adaptedfor use with different devices under test. Another feature and advantageis an improved carrier having reduced mass, increased stiffness, andgreater omni directional airflow around the drive. This carrier alsoprovides a simple pull/push or pull/push/twist motion to unclamp, toeject, and to prepare to reclamp another drive for test. In addition,the carrier provides clear access to the ends of the drive at all time,thus simplifying cable connections. Yet another feature and advantage isthat the present invention provides a practical, implementable,multi-drive test chamber testing system and design that providesimproved uniformity of temperature control, environmental conditionvariation throughout the chamber by design, product testing flexibility,and capability for small batch and/or single “unit” testing. These andother features, aspects, and advantages will become better understoodwith reference to the following description, appended claims, andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one carrier embodiment showing the top,right, and front faces.

FIG. 2A is an exploded view of two a clamping and release mechanismembodiments

FIG. 2B is a detailed view of an alternate clamping and releasemechanism.

FIG. 2C is a detailed view of a further alternative claiming and releasemechanism.

FIG. 3 is an isometric view of a carrier embodiment adapted to receivemultiple drive sizes.

FIG. 4 is a perspective view of one embodiment of the present inventionshowing a hard drive being inserted into the test bed and a handle in a“home” (load/unload) position.

FIG. 5 is a perspective view of one embodiment of the present inventionshowing a hard drive fully inserted into the test bed and the handle ina “clamping” position.

FIG. 6 is a perspective view of an environmental test chamber palletembodiment showing the top and right sides.

FIG. 7 is a bottom view of an environmental test chamber palletembodiment of FIG. 6.

FIG. 8 is a perspective view of an environmental test chamber frameembodiment containing one pallet.

FIG. 9 is a front view of an environmental test chamber frame embodimentcontaining a plurality of pallets.

FIG. 10 is a perspective rear view of an environmental test chamberframe containing a plurality of pallets and a test interface device.

FIGS. 11A-11C are detailed top, front, and side plan views of anenvironmental chamber brick.

FIG. 12 is an isometric view of a carrier drawer embodiment for use withthe dual plenum temperature control system.

FIG. 13 is an isometric view of an environmental test chamber embodimenthaving a dual plenum temperature control system.

FIG. 14 is an isometric view of a single plenum temperature controlsystem.

FIG. 15 schematically illustrates a multizone dual duct embodiment.

FIG. 16 schematically illustrates a multizone thermal-reheat embodiment.

FIG. 17 schematically illustrates an alternate variable-air-volumesystem.

FIG. 18 is an isometric view of a environmental test chamber having aplurality of drawers.

FIG. 19 is an elevational side view of an environmental test chamberframe embodiment.

DETAILED DESCRIPTION

The accompanying figures and this description depict and describeembodiments of the present invention, and features, aspects, andcomponents thereof. With regard to means for fastening, mounting,attaching or connecting the components of the present invention to formthe mechanism as a whole, unless specifically described otherwise, suchmeans are intended to encompass conventional fasteners such as machinescrews, nut and bolt connectors, machine threaded connectors, snaprings, screw clamps, rivets, nuts and bolts, toggles, pins and the like.Components may also be connected by welding, adhesives, friction fittingor deformation, if appropriate. Electrical connections or positionsensing components may be made using appropriate electrical componentsand connection methods, including conventional components andconnectors. Unless specifically otherwise disclosed or taught, materialsfor making components of the present invention are selected fromappropriate materials such as metal, metallic alloys, fibers, plasticsand the like, and appropriate manufacturing or production methodsincluding casting, extruding, molding and machining may be used. Inaddition, any references to front and back, right and left, top andbottom and upper and lower are intended for convenience of description,not to limit the present invention or its components to any onepositional or spacial orientation.

I. Hard Drive Carrier

FIG. 1 is a perspective view of the top, right, and front sides of onecarrier embodiment 10. The carrier 10 includes a frame 12, a clampingmechanism 14, and a connector bar 16. The frame 12 comprises an “L”shaped right side frame member (“right side bar”) 18, a left side framemember (“left side bar”) 20 that is generally parallel to and coplanarwith the right side bar 18, and a plurality of generally transversecross members (“cross bars”) 24 that cooperate with the right side bar18 and the left side bar 20 to define a rectangular test bed 26. Theclamping mechanism 14 in this embodiment comprises a cylindricaloperating rod 30, a linear cam 32, a linear return spring 34, a clamppad 36, an ejection lever 37, an ejection bumper 38, a non-interferinghandle 40, and a hinge 42. The connector bar or module 16 comprises avariety of electrical connections, such as a power supply port 50, anI/O port 52, and a configureable jumper port 53.

In operation, the user may first eject a previously tested drive (the“old drive,” not shown) by pulling the handle 40 outward, away from theframe 12. This pulling of the handle 40: (i) causes the clamp pad 36 tomove away from and out of engagement with the drive's right sidesurface, which frees the drive; and (ii) causes the ejection lever 37 topivot inwardly around the hinge 42, toward the old drive's rear surface,which causes the ejection bumper 38 to first contact and then push theold drive out of engagement with the connector bar 16. The handle 40 maynow be released, coming to rest in a position where the clamp pad 36 isin a withdrawn position. That is, the operating rod 30, with its linearcam 32, automatically returns to an intermediate position (“home”)determined by the maximum extension of the return spring 34. The olddrive can now be removed and replaced with the next drive to be tested(a “new drive,” not shown). The new drive should be inserted into testbed 26 with sufficient force so that it engages the connector bar 16,thus electrically connecting the new drive's electrical ports to thecorresponding ports on the connector bar 16. The handle 40 is thenpushed toward the frame 12 into a clamping position, which causes theclamp pad 36 to engage and to lock the new drive in the test bed 26.

The frame 12 in some embodiments comprises a plurality of cross members24. These cross members 24 are designed to maximize the carrier'sstiffness, yet allow for excellent omni-directional air flow. In someembodiments of the present invention, the cross members 24 may be acombination of beams having “U” shaped cross sections, “T” shaped crosssections, and/or rectangular cross sections. These embodiments aredesirable because the cross members 24 define four air flow apertures54. These apertures 54 allow temperature and humidity controlled air toflow around the bottom and side surfaces of the drive during a test.Embodiments having “U” and “T” shaped cross sections may be particularlydesirable because they can provide greater stiffness than a rectangularcross section of similar weight. This allows the manufacturer to useless material, which reduces their cost of manufacturing, reduces thephysical workload involved in a test chamber operation, and increasesthe size of the apertures 54. Some embodiments may also include one ormore diagonal cross members 24 (not shown) that further increase thecarrier's stiffness.

In some embodiments, the cross members 24 may also define four supportsor legs 56. These supports 56 are desirable because they further enhanceair flow across the bottom surface of the drive, which helps to reducethermal gradients and to increase heat transfer. These supports 56should be sufficiently strong to hold the combined weight of the driveand the carrier 10 and should be relatively wear resistant. However,embodiments without these supports 56 are also within the scope of thisinvention.

The frame 12 may be made from any material with relatively goodstiffness. One suitable material is cold rolled steel. This material isdesirable because it is relatively inexpensive, is easy to machine, anddoes not outgas. However, other materials are within the scope of thepresent invention. These include, without being limited to, grey castiron, hot rolled steel, aluminum, polyethylene, polyvinyl chloride.Dissipative plastics may also be desirable because they are lightweight,relatively inexpensive, and help to further isolate the device undertest from vibrations.

The handle 40 in this embodiment of the present invention has agenerally vertical orientation and is designed so that it does notinterfere with access to the front of the hard disk drive. This handle40 embodiment is desirable because it allows for easier connection andarrangement of cables. This handle 40 embodiment is also desirablebecause it provides a relatively large opening 41 without interferingwith drive insertion and removal. However, other handle 40configurations, orientations, and positions are within the scope of thisinvention. This specifically includes, without being limited to, ahandle 40 specially adapted for automated or robotic handling.

The clamp pad 36 in this embodiment has a relatively large clampingsurface 46, which helps to reduce the potential of mechanical motion ofthe drive relative to the frame 12. The clamping pad 36 may be alsofabricated from a resilient vibration damping material or may have astrip 47 of this material attached to the clamping surface 46. Onesuitable vibration damping material is manufactured by Aero E.A.R.Specialty Composites with a part number of C-1002-06 PSA. Theseembodiments are desirable because the vibration damping material reducestest noise, thus improving the test results. However, clamping pads 36made from other materials and/or without the vibration damping strip 47are within the scope of this invention.

The clamping mechanism 14 in some embodiments may include a rotatablejoint (not shown), such as an eye bearing, that allows the clamp pad 36to engage a drive of the drive's orientation (i.e., allows the clamp pad36 to provide clamping force in a 180 degree range). These embodimentsare desirable because they automatically allow the carrier 10 to holdnon-rectangular devices under test.

The drive ejection bumper 38 is designed and located to provide acompliant, yet firm, contact with a wide variety of drives so that itcan facilitate their removal from the carrier 10. One suitable materialis a solid, but relatively compliant, elastomeric material, such asrubber. However, other materials and designs, such as a foamed polymerbumper or an air filled bumper, are within the scope of this invention.

The connector bar 16 in some embodiments may contain a single port or aplurality of ports 50, 52 and 53 that are designed to engagecorresponding connector port(s) located on the drive. These ports 50,52, and 53 provide power to the drive and could transmit information toand from the drive.

The connector bar 16 in some embodiments is removably attached to theframe 12 by suitable means, such as a groove 70 designed to accept aportion of the connector bar 16 below fingers 72 (FIG. 2A). These“modular” connector bars 16 are desirable because the carrier 10 may bequickly configured to engage drive types and models that use differentbus interfaces, such as IDE, PCI, ATA, or SCSI. That is, users caneasily attach different, interchangeable connector bars 16 to the frame12 whenever the user needs to test drives having a particular interface.Despite this advantage, however, connector bars 16 that are permanentlyattached to the frame 12 are also within the scope of this invention.

The right side bar 18 and the left side bar 20 in this embodimentinclude a pressure strip 44 of metal-covered vibration damping material.One suitable pressure strip 44 is manufactured by Aero E.A.R. SpecialtyComposites with a part number of SB-40-ALPSA. This pressure strip 44 isdesirable because it provides good wear resistance and reducesvibrations. However, carriers 10 without this pressure strip 44 or witha pressure strip 44 made from other materials capable of dampingvibration and resisting wear are within the scope of this invention.

FIG. 2A is an expanded view showing a first embodiment of the clampingmechanism 14. FIG. 2A comprises an operating rod 30 having largediameter section 59 and a grooved section 60 that combine to form thelinear cam 32. The diameter of the large diameter section 59 is designedsuch that the operating rod 30 can slide freely through a hole 62 in theclamping pad 36. FIG. 2A also shows an actuating spring 64 and a hingepin 66.

In operation, the grooved section 60 is aligned with the hole 62 whenthe operating rod 30 is in a fully inserted or “clamping” position. Inthis position, there is sufficient space between the operating rod 30and the hole 62 such that the actuating spring 64 can pivot the clampingpad 36 around the hinge pin 66 and into engagement with the hard drive.That is, the actuating spring 64 can bias the clamping pad 36 againstthe hard drive when the grooved section 60 is laterally aligned with thehole 62. Sliding the operating rod 30 out of the “clamping position”laterally aligns the wide diameter portion 59 of the operating rod 30with the hole 62. In this position, the wide diameter section 59 of theoperating rod 30 engages the interior surface of hole 62 and preventsthe actuating spring 64 from biasing the clamping pad 36 against thedrive. That is, the operating rod 30 prevents the clamping pad 36 fromengaging the drive whenever the grooved section 60 is not aligned withthe hole 62.

The operating rod 30 in this embodiment also comprises a flat section 80that is adapted to slide freely through a slot 82 in the ejection lever37. A pin 68 fits into a corresponding hole 69 in the flat section 80.Pulling the operating rod 30 from the clamping position to a partiallyinserted or “home” position causes the flat section 80 to laterallyslide through the slot 82. This, in turn, causes the pin 68 to engage aback face 74 of the ejection lever 37. Continuing to pull the operatingrod 30 from the home position to a substantially withdrawn or “ejection”position causes the pin 68 to exert a force against the back face 74 ofthe ejection lever 37. This force pivots the ejection lever 37 aroundthe hinge 42 in a clockwise direction (as depicted in FIG. 2A), which,in turn, biases the ejection bumper 38 against the drive. The force fromthe ejection bumper 38 pushes the drive out of engagement with theconnector bar 16. Thus, pulling the operating rod 30 from the clampingposition to the ejection position releases the clamp and biases thedrive away from the connector bar 16.

Moving the operating rod 30 from the home position to the ejectionposition also causes a flange 90 on the ejection lever 37 to compressthe return spring 34 against the frame 12. When the operator releasesthe handle 40, the return spring 34 produces a force that pivots theejection lever 37 around the hinge 42 in a counterclockwise direction(as depicted in FIG. 2A). The ejection lever 37, in turn, biases theoperating rod 30 from the ejection position to the home position.

The flange 90 is designed to slide in a slot 91 between two stops 92 and94. The front stop 92 prevents the operating rod from being pulled toofar out of the frame. The rear stop 94 is positioned so that it engagesthe flange 90 when the operating rod 30 returns to the home positionfrom the ejecting position. This prevents the ejection lever 37 and thereturn spring 34 from exerting force on the operating rod 30 between thehome position and the clamping position. That is, the stop 94 isolatesthe operating rod 30 from the return spring 34 between the home positionand the clamping position. After the flange 90 hits the stop 94, theoperating rod 30 may continue to be pushed through the slot 82 from thehome position to the clamping position.

In a second embodiment clamping mechanism embodiment, the operating rod30 may also be contoured along its length to form the linear cam 32. Inthis embodiment, the sections having a greater diameter may force theclamp pad 36 to move “inward” into the test bed and into contact withthe hard disk drive. The portions of the operating rod having a smallerdiameter may allow the clamp pad 36 to move “outward,” which releasesthe hard drive. The greater diameter sections in these embodiments arepositioned along the length of the operating rod 30 such that the clamppad 36 is forced to engage the drive when the handle 40 is in the“pushed in” or “clamping” position. The smaller diameter sections arepositioned along the length of the operating rod 30 such that the clamppad 36 can release the hard disk drive when the handle 40 is in the“home” and “ejection” positions.

The return spring 34 may also be used in the second embodiment toactuate the handle 40 from an “ejection” position to a “home” position.It is desirable, however, that the return spring 34 be configured sothat it does not disengage the clamp pad 36 from the drive. In someembodiments, this may be accomplished by designing the spring's“neutral” position to correspond to the handle's “clamping” position. Itis also desirable that the chosen spring constant be low enough, or thatthe spring 34 be counter-balanced by a second spring (not shown), so asto prevent the return spring 34 from actuating the operating rod 30 intothose positions where the greater diameter sections engage the clamp pad36. Other springs 34 and mechanisms that are capable of actuating thehandle 40 from the “withdrawn” position to the “home” position and thatdo not disengage the clamping mechanism 14 during use are also withinthe scope of this invention.

One advantage of these two carrier 10 embodiments is that the loading,clamping, and ejection mechanisms are all operated by one rod using asimple push/pull motion. This simple push/pull operation of the clampingmechanism 14 may minimize the risk of repetitive motion conditions, sucha carpal tunnel syndrome, when compared to the rotational sweep clampingmechanisms found in conventional industry designs.

FIG. 2C shows a third cam mechanism embodiment 14 a that is partiallyactuated using rotational motion, which may be desirable for use withrobotic loading/unloading devices. The machined portions 60 a of rod 30in these embodiments act as a rotary cam, rather than a linear cam. Thatis, the machined area 60 a will have a large diameter arc and a smalldiameter arc. Rotating the handle 40 by about ninety degrees in eitherthe clockwise or counterclockwise direction will cause the largediameter arc to alternately engage and disengage the interior surface ofthe hole 62, which, in turn, will latch and unlatch the clampingmechanism 36. Those skilled in the art will recognize that embodimentsusing this rotational cam mechanism 14 a may replace the flat section 80with a round finger 80 a, as depicted in FIG. 2B. This finger 80 a, likethe flat section 80, should be sized to fit into the slot 82 and shouldhave a hole 69 capable of receiving the pin 68.

FIG. 3 is an isometric view of a carrier embodiment 300 adapted toreceive and test both 2.5″ and 3.5″ hard disk drives. This carrierembodiment 300 includes a second, intermediate L-shaped bar 302 that isgenerally parallel with, but vertically offset (“recessed”) from, theright side bar 18 and the left side bar 20. The intermediate side bar302 in this embodiment has a generally vertical side surface 304, apressure strip 306 adhesively attached to the generally vertical sidesurface 304, a top surface 308, a rear locator surface 309, and agenerally horizontal or slightly inclined bottom surface 310. Thecarrier 300 also comprises three crossbars 24 having an angled notch 320that generally extends between the intermediate bar 302 and the rightside bar 20. The angled bottom surface 310, the angled notch 320, andthe right side bar 20 cooperate to define a second rectangular test bed312. The carrier embodiment 300 in FIG. 3 may use either the linearlatch system or the rotary latch system described with reference toFIGS. 2A-2B.

In operation, when the carrier 300 is used with 3.5″ drives, it operatessimilar to the carrier embodiment 10 described with reference to FIGS.1-2 and 4-5. More specifically, the 3.5″ drive sits in the firstrectangular test bed 26 in a generally horizontal position and is heldin place by the left side bar 18 and the right side bar 20. Because thetop surface 308 of the intermediate bar 302 is coplanar with or belowthe horizontal surface 314 of the left side bar 18, the intermediate bar302 does not affect the insertion, testing, or removal of a 3.5″ drive.

2.5″ drives are inserted into the second rectangular test bed 312,between the intermediate side bar 302, the right side bar 20, and therear locator surface 309. Because the intermediate side bar 302 isrecessed below the left side bar 18, the 2.5″ drive will sit in thesecond rectangular test bed 312 at an acute angle to the horizontal.That is, the 2.5″ drive will rest in and be aligned with the notch 310.Actuating the clamping mechanism causes the clamp pad 36 to pivot aroundthe rotatable joint (not shown) and to engage the side of the drive,which clamps the drive in the inclined position.

The carrier embodiments in FIGS. 1-5 offer many advantages over the art.These advantages include excellent vibration reduction, minimal airflowrestriction, and single cam operation (i.e., clamp, probe and latch).Some carrier embodiments also: (i) allow for both automated and manualloading; (ii) can switch rapidly between different drive sizes; and(iii) can switch rapidly between different I/O standards.

II. Modular Pallets

Another aspect of the present invention is the use of a “building block”approach to eliminate the limitations associated with the “classic”methods of constructing environmental chambers and to provide anenvironmental test chamber that is both flexible and easy to assemble.

FIG. 6 shows a modular “carrier pallet” embodiment 100. These pallets100 are adapted to fit into a front frame 111 a and a rear frame 111 bthat define a plurality of interior receiving slots 106 a and exteriorreceiving slots 106 b (see FIGS. 8, 9, and 10). Each pallet 100comprises an insulating/air plenum brick 104 connected to a base plate105 by one or more bolts 107. The brick 104 in this embodiment defines atesting space (A), a wall space (B), and a tester space (C). The testspace (A) is designed to accommodate a fixture for holding the deviceunder test, such as the holding fixture 10 or 300, and to allowconnection to a test driving electronic package 103 via flat cable(s)102 (FIG. 7). The tester space (C) is likewise designed to allow easymounting of, and connection to, the tester driving components 103. Thewall space (B) is designed to minimize the quantity of metal and otherconductive materials, thus minimizing thermal transfer between A & C,commiserate with maintaining appropriate rigidity and mechanicalintegrity of the entire pallet.

In operation, when multiple loaded pallets 100 are inserted into slots106, the sides of the bricks 104 seal against each other and against thewalls of the test chamber. Thus, as shown in FIG. 19, the bricks 104 inthe different pallets cooperate to form a complete insulating barrier(“wall”) between the devices under test and the test driver components.That is, each brick 104 in an interior slot 106 a will seal against thebricks 104 on the pallet 100 immediately above it, below it, to itsleft, and to its right (i.e., its “neighboring bricks”). Each brick 104in an exterior slot 106 b will seal against the side of theenvironmental test chamber and three neighbor bricks 104. Users willcontinue to fill the slots 106 until the entire wall is complete.

In some embodiments, the wall may be completely formed using the pallets100 depicted in FIG. 6. In other embodiments, the wall may be partiallyformed using these pallets 100 and completed by the user of “fillerpallets” 120 similar to those shown in FIGS. 6-9, but without the deviceunder test or the electronic testing package 103 (see FIGS. 9-10 and19). These filler pallets allow a drive manufacturer to test fewerdevices at a time than would be necessary to complete the wall. That is,the filler pallets 120 may substitute for “standard” pallets, therebyallowing the user to test an arbitrary number of devices in one batch.These filler pallets 120 may be particularly desirable for use in theexterior slots 106 b to further isolate the devices under test fromenvironmental noise.

The insulating/air plenum brick 104 embodiment in FIG. 6 is about 3″thick, 3″ high and 6″ long, fabricated from a suitable lightweightinsulating material, such as expanded polystyrene foam (see also FIGS.11A-C). Polystyrene foam is desirable for this application because it islightweight, relatively durable, and inexpensive. However, otherinsulating materials are within the scope of the present invention.These include, without being limited to, polyethylene foam, urethanefoam, ethylene vinyl acetate (“EVA”) foam, asbestos, cork and otherwoods, organic bonded glass fibers, foam rubber, sponge rubber, andmetallic foil laminates.

The two ends and top of the bricks 104 in this embodiment have a pair ofstrips of sealing material, such as a nylon “hook and loop” material 108having the“loop” strips, near their outer edges. These strips aredesirable because they form a seal or diffusion barrier between thetesting space (A) and the tester space (C). The bottom of the brick 104may have a similarly placed pair of seals 109 fabricated from acompliant sealing material capable of sealing between the flat cables102, such as an ethylene propylene diene monomer (“EPDM”) sponge rubberavailable from McMaster Carr of Chicago, Ill. Although EPDM is desirablefor the bottom seal 109 because it is very resistant to chemicals, canwithstand high temperatures for extended periods, and remains stable forlong periods of time, other sealing materials are within the scope ofthis invention.

The bricks 104 in this embodiment have a groove 110 (see FIGS. 7,11A-11C, and 19) of about 1″ wide by ⅜″ deep cut into their sidesurfaces. The grooves 110 on each brick cooperate with those on theneighboring bricks and with the walls of the test chamber to provide aplenum network for purge air. Pressurizing these air plenums with anappropriate gas, such as warm dry air, places the wall space (B) underpositive pressure relative to either the test side A or the electroniccontrol side C. This positive pressure prevents to prevent air from thetesting space (A) and the tester space (C) from crossing the wall space(B), which in turn, helps both sides or chambers to be maintained underindependent conditions of temperature and humidity.

One advantage of the modular pallet 100 is that the correspondingenvironmental test chamber can be quickly and inexpensively modified totest different devices. The modular pallet embodiment is also desirablebecause the corresponding environmental test chamber can test differentcombinations of devices at the same time. That is, some of the palletsplaced in the chamber during a particular testing “run” may contain afirst type device under test and others may contain a second type ofdevice under test. The exact percentage of the first type and the secondtype may even be changed between different runs. Flexible manufacturingplants may find this feature particularly useful because they can usethe same test chamber with their entire production.

III. Environmental Test Chamber

FIGS. 8-10 depict an environmental test chamber embodiment 150. Thistest chamber embodiment 150 comprises a front frame 111 a and a rearframe 111 b that extend between a base plate 114 and a header 116. Theframes 111 a and 111 b define the plurality of pallet supporting slots106, which are arranged in a grid. This test chamber 150 also comprisesinsulating studs 112 that further support the front frame 111 a and therear frame 111 b. The environmental test chamber also includes a mainaccess door 152 and two air handlers 154 (such as that shown FIG. 14)capable of delivering air at a desired flow rate, temperature, andhumidity.

In operation, a user will insert the pallets 100 into the slots 106,which then cooperate to form a testing chamber in the rear portion ofthe chamber 150. The user will then close the main access door 152,thereby forming a tester chamber for the test driver components in thefront portion of the chamber 150. Finally, the user will activate theair handlers 154. The air handlers 154 deliver separate air flows to thetest chamber and the tester chamber, which allows independent control ofthe temperature and humidity in both chambers.

FIG. 18 depicts an alternate environmental test chamber embodiment 202.As will be discussed in more detail below, this test chamber embodiment202 has a dual plenum air supply system 200 and a plurality of drawers250. One drawer 250 is positioned for servicing and changing fixturesand/or cables. The remaining drawers 250 are positioned in a testing oroperational position. In addition to the advantages described above,this test chamber embodiment 202 is desirable because it provides: (i) adual plenum system for supplying hot and cold pressurized mixed air at acontrolled temperature gradient or at a fixed temperature; (ii) theability to test in small batches, thus decreasing average test cycletime; (iii) high uniformity/stability of the target conditions and fasttemperature ramp rates due to its use of a small test chamber volume,high air flow, and continuous feedback; (iv) the ability to run hot andcold tests can be run simultaneously in any number of drawers 250 inembodiments where each drawer, or nest of drawers, is fed by anindependently controlled mixing plenum system; (v) a substantialreduction of internal temperature gradients provided by the smallvolume/tight control operating philosophy; and (vi) a highly compact,stackable design that can be placed back-to-back with another testchamber 202.

A. Small Batch Testing

FIG. 12 is an isometric view of a drawer 250 that is suitable for usewith the environmental test chamber 202. This drawer embodiment 250comprises four pallets 100, such as those described with reference toFIGS. 6-7, that are permanently mounted on a shelf 252. The pallets 100and the shelf 252 are designed to seal against adjacent drawer(s) 250and/or the interior of the test chamber 202, thereby creating asubstantially sealed testing subchamber 254. Each subchamber 254 has twoinlet orifices 224 in one side wall 256, two outlet orifices 226 in theopposite side wall 258, and its own temperature/humidity/air flow sensor210.

In operation, a disk drive manufacturer can load four drives in eachdrawer 250, through the front of the drawer 250. Air enters theresulting subchamber 254 from the inlet orifices 224, circulates aroundthe four drives, and exits through the outlet orifices 226. Theseembodiments are desirable because each subchamber 254 acts as a separatemini-environmental test chamber, which decreases the test's batch size.That is, the environmental conditions in each subchamber 254 aresubstantially independent of the presence or absence of other drawers250 in the test chamber 202 and substantially independent of theenvironmental conditions in the other drawers 250. This allows themanufacturer to insert one drawer 250 into the test chamber 202, bringthat drawer's subchamber 254 up to the desired testing conditions, andto conduct the desired test—all without having to completely fill theentire chamber 202 with disk drive or filler pallets. Thus, themanufacturer can perform a test on some drives while simultaneouslyloading other drives into another drawer 250. This feature is desirablebecause it can decrease the average amount of time necessary to conductthe tests and because it reduces the mass that must be heated or cooledto preform each test, as only the specific occupied drawers aremaintained at the desired test environment.

In some embodiments, the inlet orifices 224 admit blended air from asingle mixing chamber 218 and the outlet orifices 226 allow air to exitto a single return plenum 225. The sensors 210 associated with eachdrawer 250 provide a control computer 212 (FIG. 13) with continuoustemperature, humidity, and air flow rate information about thesubchamber 254. The control computer 212, in turn, adjusts the airhandling system to produce optimum uniformity and stability in targettemperatures. In these embodiments, the orifices, plenums, controlsystem, and drawers should be designed produce a small test volume, highair flow, and continuous feedback. This combination will help maximizetemperature uniformity and stability despite the changing operatingconditions in chamber 202.

In other embodiments, the sensors 210 can be used to individuallycontrol the environmental conditions in each subchamber 254 or in smallgroups of subchambers 254. These embodiments may be desirable becausehot and cold tests can be run simultaneously in any number of drawers250 and because the individual controls will further improve uniformityand stability of the target temperatures.

B. Temperature and Air Flow Rate Control

FIG. 13 is an isometric view of a dual plenum air system embodiment 200suitable for use with the environmental test chamber 202. This airplenum system 200 comprises a cold air supply duct (“cold air plenum”)204 and a hot air supply duct (“hot air plenum”) 206, both of which arepneumatically connected to a fan or blower 208 by a flow divider. Thehot air plenum 206 has a heating element 209 and can supply air at anyreasonably defined temperature above the desired test chambertemperature. The cold air plenum 204 has a cooling element 214 and cansupply air at any reasonably defined temperature below the desired testchamber temperature. The hot and cold air plenums 204 and 206 supply amixing chamber 218, which mixes and blends the hot and cold air streamsinto a uniform air stream at the target temperature and humidity. Thismixing chamber 218 includes two computer controlled dampers 219 and avariable speed fan or blower 220, and is pneumatically connected to theenvironmental test chamber 254 by the inlet orifices 224 associated witheach drawer 250 (FIG. 12). The outlet orifices 226, in turn, allow airto pass from the testing subchamber 254 into a return plenum 225. Theair plenum system 200 in some embodiments may also include a humidifier227, additional computer controlled baffles or dampers 228, and acomputer control system 212. This control system 212 is operablyconnected to a temperature, humidity, and air flow rate sensor 210located inside the environmental test chamber 254, to the dampers 219and 228, to the variable speed fan 220, and to the humidifier 227, andto the heating 209 and cooling 214 elements.

In operation, the fan 208 draws air from the return plenum 225 and/orthe ambient air outside the chamber 254, and forces it into the cold airplenum 204 and the hot air plenum 206. The air entering the cold airplenum 204 passes over the cooling element 214, where it can be cooledto a temperature below the desired test chamber temperature. Thoseskilled in the art will recognize that this can cause water to condenseout of the air stream, which decreases the air stream's humidity ratio.The air stream entering the hot air plenum 206 similarly passes over theheating element 209 and is heated above the desired test chambertemperature.

After the air passes through the cold air plenum 204 and the hot airplenum 206, the two air streams are combined and blended together in themixing chamber 218. The mixing chamber includes two computer controlledair dampers 219, one for the cold air plenum 204 and one for the hot airplenum 206, that are operably connected to the control system 212. Thecontrol system 212 can use a signal from the temperature/humidity sensor210 to actuate the dampers 219. This, in turn, adjusts the respectiveflow rates of the hot and cold air streams. The end effect is similar tothe mixing faucet on a kitchen sink, only with the fluid being airrather than water. In some embodiments, the control system 212 alsocontrols the operation of the humidifier 227 (not shown), which allowsit to selectively increase the humidity of the blended air stream.

The fan 220 draws air from the mixing chamber 218 and pushes it throughthe inlet orifices 224, into the environmental test chamber 254. Afterthe air has circulated around the devices under test, it exits the testchamber 254 through the outlet orifices 224. A damper 228 in the returnplenum 225 can then either direct the air stream back into the fan 208,vent it to atmosphere, or a combination thereof, depending on whichchoice is the more energy efficient for the desired test conditions.

The heating element 209 may be any device capable of heating the airstream flowing through the hot air plenum 206. Suitable devices include,without being limited to, an electrical heating element or a heatexchanger connected to supply of hot water or steam. The cooling element214 may similarly be any device capable of cooling the air streamflowing through the cold air plenum 204. Suitable devices include,without being limited to, a heat exchanger connected to a supply ofchilled water or may be a vapor-compression cycle refrigeration unit.The temperature/humidity/air flow sensors 210 may be any device, orcombination of devices, capable of sensing the temperature, humidity,and air flow inside the test chamber or chambers.

The baffles or dampers 219 and 228 can be any device, or combination ofdevices, that can control and change the flow rate of air through aduct. Computer controlled baffles or dampers 219 and 228 areparticularly desirable because they will allow a user to quickly andeasily change the conditions inside the test chamber 254. However,manually actuated devices 219 and 228 are also within the scope of thepresent invention.

The air delivery system in FIG. 13 is depicted as vertically surroundinga cluster of drawers 250 (FIG. 12). These vertical embodiments aredesirable because the air delivery system 200 can be easily built aroundthe test chamber 254 such that the chamber/air delivery system form asingle, integrated unit. However, the air delivery system 200 could belocated at any other angle relative to the drawers 250 and could feedone drawer 250 or a plurality of drawers 250.

The control system 212 can be any device or combination of devicescapable of maintaining the conditions inside the test chamber(s) at ornear the target conditions. In some embodiments, the control unit 212 isan microprocessor implemented active feedback control system that usesthe signal from the sensors 210 to operate the dampers 219 and 228, thevariable speed fan 220, and the humidifier 227. Other suitablecontrollers include, but are not limited to, an analog or digitalfeedback device running an appropriate control algorithm.

Many variations of the embodiment in FIG. 13 are within the scope of thepresent invention. For example, the cooling element 214 may beeliminated. The cold air plenum 204 in this embodiment will then supplyeither ambient\room temperature air or return temperature air to themixing chamber 218, depending on which is more energy efficient for thedesired test conditions. In addition, the present invention may includea flow straightener between the mixing chamber and the inlet orifice224. This flow straightener can be any device capable of reducing oreliminating the turbulence caused by the fan 220. Suitable devicesinclude, but are not limited to, a bank of tubes or honeycomb structurethat forms a plurality of small diameter flow paths. The flowstraightener may be desirable for its potential to reduce vibrationscaused by uneven air flow.

FIGS. 15, 16 and 17 schematically depict alternate air delivery systemembodiments suitable for use with the multiple, independentlycontrollable subchambers 254 described with reference to FIGS. 12 and13. Specifically, FIG. 15 depicts a dual duct variable-air-volume(“VAV”) system in which each subchamber 254 has its own mixing chamber218. FIG. 16 depicts a multizone single plenum system with terminalreheat. In this embodiment, all of the air is cooled to a temperaturelow enough to assure dehumidification. The sensor 210 in each subchamber254 is used to control its associated reheat coil 209 to insure that theair entering each subchamber 254 is at the proper temperature andhumidity. FIG. 17 depicts a single plenum VAV system with terminalreheat. Terminal reheat systems like those shown in FIGS. 16 and 17 maybe desirable because they only require a single duct. This feature candecrease the system's initial cost and complexity. Dual duct systemslike that shown in FIG. 15, however, are more energy efficient. Thiswill decrease the system's operating costs.

One particular embodiment of the present invention incorporates allthree aspects described above designed and operates in a synergisticmanner to produce excellent uniformity of temperature/humidity and airflow on the test side and minimal heat transfer between the test andtester sides due to the excellent thermal insulation provided by thebricks, their framework, the constructed the air plenum system, and thewarm dry air purge pushed into the plenum. In this embodiment, thepallet 100 is fabricated from cold rolled steel, the framework 111 a and111 b is fabricated from cold rolled steel, powder coated; the insulatedstuds 112, the base plate 114 and header 116 are fabricated from a gradeXX paper/phenolic laminate sold under the trade name GAROLITE byMcMaster Carr of Chicago, Ill.; the insulating bricks 104 are fabricatedfrom the RayLite® brand expanded polystyrene produced by DiversiFoamProducts of Rockford, Minn.; the rubber seals are fabricated from EPDMsponge rubber; and the brick 104 top and side closure are fabricatedfrom the “loop” material of nylon “hook and loop” fabric.

Although the present invention has been described in detail withreference to certain examples thereof, it may be also embodied in otherspecific forms without departing from the essential spirit or attributesthereof. For example, although present invention have generally beendescribed with reference to a computer hard drive, and in particular forenvironmental testing of 3.5 inch and 2.5 inch, disk drives, theprinciples could be extended to controlled environment testing of otherdevices. These include, without being limited to, compact disk (“CD” or“CD-ROM”) drives, digital video disk (“DVD”) drives, tape drives,“cards” for computer peripherals, computer memory chips, integratedcircuit wafers, personal computer devices, consumer electronics, etc.Aspects of the present invention can also be used as an incubator, orthe like, in biological manufacturing processes and testing. Inaddition, the carrier and/or the pallets may include auxiliary fandesigned to improve airflow around the device under test. Therefore, itis desired that the embodiments described herein be considered in allrespects as illustrative, not restrictive, and that reference be made tothe appended claims for determining the scope of the invention.

What is claimed is:
 1. An environmental test chamber apparatuscomprising: a test volume; a plenum system; and a plurality of drawersreceived in the test volume, each drawer in communication with theplenum system and each drawer cooperating with the test volume and eachother to generally seal each drawer.
 2. The apparatus of claim 1, andfurther comprising an air temperature control.
 3. The apparatus of claim1, and further comprising a humidity control.
 4. The apparatus of claim1, wherein the plenum system includes a hot supply plenum and a coldsupply plenum.
 5. The apparatus of claim 1, and further comprising asensor associated with each drawer, wherein the sensors are in operablecommunication with a controller.
 6. The apparatus of claim 5, whereinthe plenum system includes a fan controlled by the controller, the fanbeing adapted to control the flow of air to the test volume.
 7. Theapparatus of claim 5, wherein the plenum system includes a hot plenumdamper and a cold plenum damper, and wherein both are controlled by thecontroller.
 8. The apparatus of claim 7, wherein the plenum systemincludes a mixing chamber in operable communication with the hot plenumdamper and the cold plenum damper.
 9. The apparatus of claim 5, whereinthe controller is a feedback controller.
 10. The apparatus of claim 1,further comprising a plurality of inlets, wherein each drawer in theplurality of drawers is in independent operable communication with atleast one inlet in the plurality of inlets.
 11. The apparatus of claim10, further comprising a plurality of plenums in operable communicationwith the plurality of inlets.
 12. The apparatus of claim 11, whereineach plenum in the plurality of plenums can be operated at differentenvironmental conditions.
 13. The apparatus of claim 1, wherein eachdrawer is adapted to receive a device under test.
 14. The apparatus ofclaim 1, wherein each drawer is adapted to receive a plurality of discdrives.
 15. A testing apparatus, comprising: a housing; a plurality ofdrawers received in the housing, each drawer in communication with aplenum system and each drawer cooperating with the housing and eachother to generally seal each drawer; a plenum system in communicationwith each drawer; and a controller to regulate flow of air from theplenum system into each drawer.
 16. The apparatus of claim 15, andfurther comprising a plurality of sensors, each sensor located within adrawer and each in communication with the controller.
 17. The apparatusof claim 16, wherein the controller regulates temperature in each drawerindependently.
 18. An environmental test chamber comprising: a pluralityof drawers, the drawers being thermally sealed from each other; a plenumsystem in communication with each drawer; and a controller coupled tothe plenum system, the controller controlling the temperature in eachdrawer individually.
 19. A disc drive tester apparatus comprising: aplurality of drawers; a disc drive carrier disposed in a drawer; aplenum system comprising a plurality of plenums, each in communicationwith an individual drawer; an air delivery system in communication witheach plenum; and a controller coupled to the plenum system, thecontroller controlling the temperature in each drawer individually. 20.The apparatus of claim 19, and further comprising a humidity control.21. The apparatus of claim 19, and further comprising a sensorassociated with each drawer, wherein the sensors are in operablecommunication with the controller.
 22. The apparatus of claim 21,wherein the plenum system includes a hot plenum damper and a cold plenumdamper, and wherein both are controlled by the controller.
 23. Theapparatus of claim 22, wherein the controller is a feedback controller.